JP3387148B2 - Liquid crystal panel driving device and data conversion method used in the driving device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a liquid crystal panel using a simple matrix system and a data conversion method used in the drive device.

[0002]

2. Description of the Related Art In recent years, a display device such as a liquid crystal display device has been an indispensable technology as a man-machine interface. Especially, in recent computer terminals and the like, the liquid crystal display device is not suitable for downsizing. It has become mandatory. Among them, the simple matrix type liquid crystal display device is
Prices are in a reasonable range and it is being used widely.

Conventionally, as a driving method of a simple matrix type liquid crystal display device, line-sequential scanning of scanning lines is used in accordance with the voltage averaging driving method. This method is mathematically considered as follows. That is, the number of scanning lines is N,
Assuming that the applied voltage of the selected scanning line is 1 and the applied voltage of the unselected scanning line is 0, selecting one scanning line in sequence at each moment means that N scanning electrodes of the liquid crystal panel are arranged. When the direction is the row direction and the time transition direction is the column direction, it corresponds to generating an Nth-order unit matrix as a whole and driving each scanning line. Hereinafter, it is assumed that the rows and columns of the matrix are defined by mathematics, and the definition of the rows and columns in the liquid crystal panel of the simple matrix system is that scanning lines correspond to rows and signal lines correspond to columns. .

When this method is used in a high-speed liquid crystal panel, each scanning line becomes bright once for a frame and then becomes dark immediately, and as a result, the liquid crystal panel transmits a white state and a light does not pass. The contrast, which is the ratio of brightness in the black state, is considerably lower than expected. Further, when used in a normal liquid crystal panel, this state is maintained for one frame or more when it becomes bright due to an instantaneous large voltage pulse. Such a phenomenon is called a frame response.

Therefore, recently, the following driving method has been devised. It is obtained by dispersing one row of the nth-order orthogonal matrix X as shown in (Equation 4) and filling 0 in between, and the orthogonal matrix H (having three values of 1, 0 and -1 as elements is This matrix H is obtained by the Kronecker product (Equation 7) of the matrix X and the m-th order unit matrix Y as in (Equation 6). Eyes, (Equation 9)
Is a matrix rearranged in the j'th column obtained from

[0006]

[Equation 4]

[0007]

[Equation 5]

[0008]

[Equation 6]

[0009]

[Equation 7]

[0010]

[Equation 8]

[0011]

[Equation 9]

The term "orthogonal" as used herein means that the inner product of any two different row vectors among the row vectors forming the matrix is always 0. Of such an orthogonal matrix,
A column signal matrix B is created by selecting a matrix H such that m × n is equal to N and performing a multiplication with an image data matrix A of N rows and M columns corresponding to image data of one frame.

Next, this orthogonal matrix H is used for the matrix representing the temporal change of the drive signal of each scanning line of the liquid crystal panel, which was a unit matrix in the voltage averaging drive method, and in the case of -1,
In the case of 1, the voltage whose polarity is inverted is applied to the scan electrodes. That is, this is equivalent to selecting n scanning lines at a time instead of line-sequential scanning. Then, at a time t when one frame period is divided into N equal parts, a voltage according to the value of each element of the t-th row of the matrix H is applied to the scan electrode, and at the same time, each element of the t-th row of the column signal matrix B is applied. A voltage corresponding to the value of is applied to each signal electrode. By doing so, the column signal matrix B is inversely transformed on the liquid crystal panel, and an effective voltage according to each element of the original image data can be applied to each pixel.

By increasing the number of scanning lines selected in this way and dispersing the effective voltage applied to each pixel within one frame, the voltage peak value is lowered as compared with the voltage averaging driving method of line-sequential scanning. be able to. From this point, there is an advantage that crosstalk and frame response can be reduced and image quality can be improved.

This method is based on Clifton, B. etc., "Hardw
are Architectures for Video-Rate, Active Addressed
STN Displays, "Proceedings of the 12th Internatio
nalDisplay Research Conference, pp.504-506, Oct.199
For more details on 2. and the orthogonal matrix and Kronecker product, see "Code Theory", Hiroshi Miyakawa et al., Shokodo.

[0016]

However, as described above, in the circuit for converting the image data using the matrix having ternary values of 1, 0 and -1, in order to perform the multiplication with the element of 0. However, there is a problem in that the circuit scale and the calculation time are wasted.

The present invention solves the above-mentioned conventional problems. As a result, each element is simply operated with a matrix consisting of binary values of 1 and -1. It is an object of the present invention to provide a data conversion method capable of performing an operation with a matrix of three ternary values of 1 and reducing the scale of an operation circuit, and a liquid crystal panel drive device using this conversion method.

[0018]

In order to achieve this object, the present invention provides an image data buffer memory for storing an image data matrix A of N rows and M columns input from the outside, and each element is 1 and -1. The matrix generating means for generating an n-th order orthogonal matrix X consisting of and the data of one column of the image data matrix A constitutes an n-row m-column matrix a in which the total number of data is N. The conversion means for converting the image data matrix A into the column signal matrix B by performing the calculation of the product of X and the matrix a for all columns of the image data matrix A, and the conversion data for storing the column signal matrix B A buffer memory, a liquid crystal display means using a simple matrix system, and an extension from the orthogonal matrix X,
The driving means is configured to drive the liquid crystal display means from an N-order orthogonal matrix H in which the elements are arranged in a column of an N-order orthogonal matrix Z consisting of 1, 0 and -1, and a column signal matrix B. .

[0019]

According to the present invention, with the above-described structure, each element is simply operated with a binary matrix of 1 and -1, and as a result, a matrix of ternary elements of 1, 0 and -1 is obtained. Can be calculated.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a drive device for a liquid crystal panel showing a first embodiment of the present invention.

In FIG. 1, an image data buffer memory 1 stores image data of one frame (N rows and M columns) input from the outside as an image data matrix A, and the matrix memory 2 stores 1 for each element. An n-th order orthogonal matrix X consisting of binary values of -1 is stored. The row register 3 can read the elements of the matrix X stored in the matrix memory 2 in units of rows,
This operation is sequentially performed from the first row to the nth row. For the shift register group 5 having m n-stage shift registers, the selector 4 sequentially outputs n pieces of N data in one column of the image data matrix A stored in the image data buffer memory 1 from the beginning. Data is distributed so as to be stored in one shift register. That is, this is to divide the data of one column of the image data matrix A into m column vectors consisting of continuous n data, and to obtain an n-row m-column matrix a in which the total number of data is N. Is equivalent to configuring.

The selector 6 selects one of the m shift registers while the row register 3 holds one row vector, and the data in the selected shift register is input to the arithmetic circuit 7 in parallel. The transfer operation is performed for all shift registers. Each time the arithmetic circuit 7 changes the shift register selected by the selector 6, the arithmetic circuit 7 calculates the inner product of the data transferred from the selector 6, that is, the column vector of the matrix a and the row vector of the row register 3 to obtain the matrix a. And the matrix b which is the product of the matrix X.

For this work, the column vector of the matrix A is composed of 12 elements (N = 12) as in (Equation 10), and the shift register group 5 has three shift registers of four stages (n = 4, m = 3), the matrix X of the matrix memory 2 is expressed by (Equation 4)
Will be described as a matrix. However, t in the upper left corner of (Equation 10)
Means transposition.

[0024]

[Equation 10]

First, the matrix of 4 rows and 3 columns obtained from the column vector of (Equation 10) is as shown in (Equation 11).

[0026]

[Equation 11]

Here, if the matrix obtained from the product of the matrix of (Equation 11) and the matrix X is as shown on the left side of (Equation 12),

[0028]

[Equation 12]

This matrix (Equation 12) is the matrix H (Equation 5).
And the column vector (Equation 10), which is a product of the column vector (Equation 10).

[0030]

[Equation 13]

These series of operations are performed by M of the image data matrix A.
When all columns are performed, as a result, the column signal matrix B of N rows and M columns, which is the product of the matrix H and the image data matrix A, is created in column units and stored in the conversion data buffer memory 8. It

Also, the distribution circuit 9 divides the scanning side voltage registers 10 capable of storing N pieces of data into n groups to form a total of m groups, and at time t, (equation 1
4) Using r and s obtained from 4), the data of the row register is stored so that the data of the element of the r-th row of the n-th order matrix X is stored in the sth group and 0 is stored in the other groups. Distribute. The scanning side driver 11 applies a scanning voltage to the scanning electrodes of the simple matrix type liquid crystal display device 14 according to the data stored in the scanning side voltage register 10. As a result, a voltage corresponding to the value of each element of one row of the matrix H of the Nth order is virtually applied to the N scan electrodes of the simple matrix type liquid crystal display device 14 by using the matrix X of the nth order. can do.

[0033]

[Equation 14]

On the other hand, the conversion data buffer memory 8 performs the operation of outputting each element of the column signal matrix B from the 1st row and the 1st column to the 1st row and the Mth column in order to the Nth row, and sends it to the D / A converter 12. , D / A converter 12 converts the sent digital value into an analog value and outputs it. Signal side driver 13
Is a column signal matrix B converted by the D / A converter 12.
The voltage corresponding to the M analog values corresponding to one row of
The signals are applied in parallel to the M signal side electrodes of the simple matrix type liquid crystal display device 14.

Among these components, the distribution circuit 9, the scanning side voltage register 10, the scanning side driver 11, the D / A converter 12 and the signal side driver 13 drive the simple matrix type liquid crystal display device 14. A drive block 100 is configured, and a matrix generation block 200 that generates the elements of the matrix X in units of one row is configured from the matrix memory 2 and the row register 3, and a selector 4, a register group 5, a selector 6, and an arithmetic circuit 7 are provided. From the above, a conversion block 300 for converting the image data matrix A into the column signal matrix B using the matrix H is configured.

As described above, according to the first embodiment, the image data buffer memory (image data buffer memory 1) for storing the image data matrix A of N rows and M columns input from the outside and each element is 1 N-th orthogonal matrix X consisting of 1 and -1
Generating means for generating (matrix generating block 200)
And the data of one column of the image data matrix A constitutes a matrix a of n rows and m columns in which the total number of data is N, and the product of the orthogonal matrix X and the matrix a is calculated by the image data matrix A By performing conversion on all columns of the image data matrix A into a column signal matrix B (conversion block 300), and a conversion data buffer memory (conversion data buffer memory 8) storing the column signal matrix B. Liquid crystal display means (simple matrix type liquid crystal display device 14) using a simple matrix system,
By providing the driving means (driving block 100) for driving the liquid crystal display means from the orthogonal matrix H of the Nth order, which is extended from the orthogonal matrix X and each element is composed of 1, 0 and -1, and the column signal matrix B, Each element is simply calculated with a binary matrix of 1 and -1, and as a result, each element has 3 of 1 and 0 and -1.
Calculation with a matrix of values can be performed, and the scale of the calculation circuit can be reduced.

By changing the order of the column vector of the matrix a composed of the column vector of the image data matrix A, the matrix H and the matrix X are obtained by rearranging the order of rows or columns of the m-th order unit matrix. The same effect can be obtained even if the matrix Z is obtained by rearranging the columns of the matrix Z obtained from the Kronecker product with. For example, if a matrix such as (Equation 15) is used as the matrix Y instead of the unit matrix of (Equation 6), the matrix H becomes (Equation 16).

[0038]

[Equation 15]

[0039]

[Equation 16]

In order to obtain the same effect as using the matrix H thus obtained, the matrix a of (Equation 17) is constructed from the column vector of (Equation 10), and the matrix X (Equation 4) Although the product of and may be calculated, (Expression 17) is a replacement of the columns of (Expression 11).

[0041]

[Equation 17]

Further, among the m shift registers of the shift register group 5, the data of a specific shift register is always calculated by changing the sign so that the matrix Y multiplies the row or column of the unit matrix by -1. The same effect can be obtained even with a matrix.

Further, the matrix memory 2, the row register 3, the selector 4, the shift register group 5, the selector 6, the arithmetic circuit 7, and the distribution circuit 9 can also be realized by using a microcomputer, and the effect of the invention does not change. Absent.

Next, a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, parts having the same functions as those in FIG.

The selector 20 shifts the N pieces of data in one column of the image data matrix A stored in the image data buffer memory 1 one by one in order from the beginning.
It is distributed to n m-stage shift registers. That is, this converts the data in one column of the image data matrix A into
By dividing into m groups consisting of continuous n data, and making one group into one column vector,
This is equivalent to forming a matrix a of n rows and m columns in which the total number of data is N, and the adjacent data in one shift register is n pieces of data separated in the original column vector.

Each shift register of the shift register group 21 performs m-1 cyclic shifts while the row register 3 holds one row vector, and the column register 22 has n shift registers of the shift register group 21. Latch the data at the beginning position of the shift register of. That is, the column vector of the matrix a is latched in the column register 22.

Each time the column vector of the column register 22 is updated, the arithmetic circuit 7 calculates the inner product of the column vector consisting of n pieces of data of the column register 22 and the row vector of the row register 3 to obtain the matrix a. And the matrix X are calculated.

In the second embodiment, an image data matrix is formed from such a selector 20, a register group 21, a column register 22 and an arithmetic circuit 7 using a matrix H consisting of three values of 1, 0 and -1. Transform block 4 for transforming A into a column signal matrix B
00 is used instead of the conversion block 300 of the first embodiment.

By setting the position of the data latched by the column register 22 to a position other than the beginning of the n shift registers, etc., a matrix in which the order of the rows or columns of the m-th unit matrix is rearranged is used. Even if the matrix H is configured as described above, the same effect can be obtained.

Further, the selector 20 and the shift register group 2
The first and column registers 22 can also be realized by using a microcomputer, and the effect of the invention remains unchanged.

[0051]

As has been described in detail above, according to the present invention, each element only has to be operated with a matrix consisting of binary values of 1 and -1, and as a result, each element of 1 and 0 can be obtained. It is possible to perform a calculation with a matrix consisting of three values of −1 and −1, and it is possible to reduce the scale of the calculation circuit.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a drive device for a liquid crystal panel according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a drive device for a liquid crystal panel according to a second embodiment of the present invention.

[Explanation of symbols]

1 Image data buffer memory 2 matrix memory 3-line register 4, 6, 20 selector 5,21 shift register group 7 arithmetic circuit 8 Conversion data buffer memory 9 distribution circuits 10 Scan side voltage register 11 Scan side driver 12 D / A converter 13 Signal side driver 14 Simple matrix liquid crystal display device 22 column register 100 drive block 200 matrix generation block 300,400 conversion block

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G09G 3/36 G02F 1/133 545

Claims (2)

(57) [Claims] 1. A decision is made according to the number of scanning lines selected at one time.
The n-th order (n is a natural number) that is determined is a binary value of 1 and -1
Distribute one row of the orthogonal matrix X
The three values of 1, 0 and -1 obtained by
Liquid crystal panel for driving the liquid crystal display unit using the orthogonal matrix H
In the driving device of the digital camera, an image data buffer memory for storing an image data matrix A of N rows and M columns (M and N are natural numbers) corresponding to a two-dimensional image input from the outside , and a matrix for generating the orthogonal matrix X. The generating means and one column vector of the image data matrix A are replaced by m column vectors (m is a natural number,
N = m × n) to form an n-row m-column matrix a having a total data number of N, and calculating the product of the n-th order orthogonal matrix X and the matrix a by the matrix A by performing against the M columns, said N-order orthogonal matrix H the image data matrix a
And a conversion data buffer memory for storing the column signal matrix B, a liquid crystal display device using a simple matrix system, and a time t (t is 0 or more and less than N) Value of each element on the t-th row of the column signal matrix B at the same time as applying a voltage according to the value of each element on the t-th row of the N-th order orthogonal matrix H to the scan electrodes of the liquid crystal display means. And a drive unit for driving the liquid crystal display unit by applying a voltage according to the above to each signal electrode of the liquid crystal display unit. Wherein said driving means, the N number of scanning electrodes of the liquid crystal display unit is divided into m groups of n scan electrodes consecutive, the time t obtained from equation (1) r , S, using The scanning electrodes of s-th group by applying a voltage corresponding to the value of r row elements of the matrix X, the scan electrodes of other groups by applying a voltage corresponding to 0, the matrix H 2. The liquid crystal panel drive device according to claim 1, wherein a voltage according to the value of the element of each row is applied to the N scan electrodes.